mirror of
https://git.ffmpeg.org/ffmpeg.git
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44c560003a
Originally committed as revision 8910 to svn://svn.ffmpeg.org/ffmpeg/trunk
413 lines
12 KiB
C
413 lines
12 KiB
C
/*
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* DVD subtitle decoding for ffmpeg
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* Copyright (c) 2005 Fabrice Bellard.
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avcodec.h"
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//#define DEBUG
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static int dvdsub_init_decoder(AVCodecContext *avctx)
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{
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return 0;
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}
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static int get_nibble(const uint8_t *buf, int nibble_offset)
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{
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return (buf[nibble_offset >> 1] >> ((1 - (nibble_offset & 1)) << 2)) & 0xf;
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}
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static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
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const uint8_t *buf, int nibble_offset, int buf_size)
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{
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unsigned int v;
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int x, y, len, color, nibble_end;
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uint8_t *d;
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nibble_end = buf_size * 2;
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x = 0;
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y = 0;
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d = bitmap;
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for(;;) {
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if (nibble_offset >= nibble_end)
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return -1;
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v = get_nibble(buf, nibble_offset++);
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if (v < 0x4) {
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v = (v << 4) | get_nibble(buf, nibble_offset++);
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if (v < 0x10) {
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v = (v << 4) | get_nibble(buf, nibble_offset++);
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if (v < 0x040) {
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v = (v << 4) | get_nibble(buf, nibble_offset++);
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if (v < 4) {
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v |= (w - x) << 2;
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}
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}
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}
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}
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len = v >> 2;
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if (len > (w - x))
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len = (w - x);
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color = v & 0x03;
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memset(d + x, color, len);
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x += len;
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if (x >= w) {
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y++;
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if (y >= h)
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break;
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d += linesize;
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x = 0;
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/* byte align */
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nibble_offset += (nibble_offset & 1);
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}
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}
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return 0;
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}
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static void guess_palette(uint32_t *rgba_palette,
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uint8_t *palette,
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uint8_t *alpha,
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uint32_t subtitle_color)
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{
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uint8_t color_used[16];
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int nb_opaque_colors, i, level, j, r, g, b;
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for(i = 0; i < 4; i++)
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rgba_palette[i] = 0;
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memset(color_used, 0, 16);
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nb_opaque_colors = 0;
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for(i = 0; i < 4; i++) {
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if (alpha[i] != 0 && !color_used[palette[i]]) {
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color_used[palette[i]] = 1;
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nb_opaque_colors++;
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}
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}
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if (nb_opaque_colors == 0)
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return;
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j = nb_opaque_colors;
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memset(color_used, 0, 16);
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for(i = 0; i < 4; i++) {
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if (alpha[i] != 0) {
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if (!color_used[palette[i]]) {
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level = (0xff * j) / nb_opaque_colors;
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r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
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g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
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b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
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rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
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color_used[palette[i]] = (i + 1);
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j--;
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} else {
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rgba_palette[i] = (rgba_palette[color_used[palette[i]] - 1] & 0x00ffffff) |
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((alpha[i] * 17) << 24);
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}
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}
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}
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}
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static int decode_dvd_subtitles(AVSubtitle *sub_header,
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const uint8_t *buf, int buf_size)
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{
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int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
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uint8_t palette[4], alpha[4];
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int date;
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int i;
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int is_menu = 0;
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if (buf_size < 4)
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return -1;
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sub_header->rects = NULL;
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sub_header->num_rects = 0;
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sub_header->start_display_time = 0;
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sub_header->end_display_time = 0;
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cmd_pos = AV_RB16(buf + 2);
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while ((cmd_pos + 4) < buf_size) {
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date = AV_RB16(buf + cmd_pos);
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next_cmd_pos = AV_RB16(buf + cmd_pos + 2);
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
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cmd_pos, next_cmd_pos, date);
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#endif
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pos = cmd_pos + 4;
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offset1 = -1;
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offset2 = -1;
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x1 = y1 = x2 = y2 = 0;
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while (pos < buf_size) {
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cmd = buf[pos++];
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
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#endif
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switch(cmd) {
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case 0x00:
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/* menu subpicture */
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is_menu = 1;
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break;
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case 0x01:
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/* set start date */
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sub_header->start_display_time = (date << 10) / 90;
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break;
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case 0x02:
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/* set end date */
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sub_header->end_display_time = (date << 10) / 90;
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break;
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case 0x03:
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/* set palette */
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if ((buf_size - pos) < 2)
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goto fail;
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palette[3] = buf[pos] >> 4;
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palette[2] = buf[pos] & 0x0f;
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palette[1] = buf[pos + 1] >> 4;
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palette[0] = buf[pos + 1] & 0x0f;
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pos += 2;
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break;
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case 0x04:
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/* set alpha */
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if ((buf_size - pos) < 2)
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goto fail;
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alpha[3] = buf[pos] >> 4;
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alpha[2] = buf[pos] & 0x0f;
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alpha[1] = buf[pos + 1] >> 4;
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alpha[0] = buf[pos + 1] & 0x0f;
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pos += 2;
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
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#endif
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break;
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case 0x05:
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if ((buf_size - pos) < 6)
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goto fail;
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x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
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x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
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y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
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y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
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x1, x2, y1, y2);
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#endif
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pos += 6;
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break;
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case 0x06:
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if ((buf_size - pos) < 4)
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goto fail;
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offset1 = AV_RB16(buf + pos);
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offset2 = AV_RB16(buf + pos + 2);
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#ifdef DEBUG
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av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
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#endif
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pos += 4;
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break;
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case 0xff:
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default:
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goto the_end;
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}
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}
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the_end:
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if (offset1 >= 0) {
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int w, h;
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uint8_t *bitmap;
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/* decode the bitmap */
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w = x2 - x1 + 1;
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if (w < 0)
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w = 0;
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h = y2 - y1;
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if (h < 0)
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h = 0;
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if (w > 0 && h > 0) {
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if (sub_header->rects != NULL) {
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for (i = 0; i < sub_header->num_rects; i++) {
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av_free(sub_header->rects[i].bitmap);
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av_free(sub_header->rects[i].rgba_palette);
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}
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av_freep(&sub_header->rects);
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sub_header->num_rects = 0;
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}
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bitmap = av_malloc(w * h);
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sub_header->rects = av_mallocz(sizeof(AVSubtitleRect));
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sub_header->num_rects = 1;
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sub_header->rects[0].rgba_palette = av_malloc(4 * 4);
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decode_rle(bitmap, w * 2, w, (h + 1) / 2,
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buf, offset1 * 2, buf_size);
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decode_rle(bitmap + w, w * 2, w, h / 2,
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buf, offset2 * 2, buf_size);
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guess_palette(sub_header->rects[0].rgba_palette,
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palette, alpha, 0xffff00);
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sub_header->rects[0].x = x1;
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sub_header->rects[0].y = y1;
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sub_header->rects[0].w = w;
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sub_header->rects[0].h = h;
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sub_header->rects[0].nb_colors = 4;
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sub_header->rects[0].linesize = w;
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sub_header->rects[0].bitmap = bitmap;
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}
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}
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if (next_cmd_pos == cmd_pos)
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break;
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cmd_pos = next_cmd_pos;
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}
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if (sub_header->num_rects > 0)
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return is_menu;
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fail:
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return -1;
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}
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static int is_transp(const uint8_t *buf, int pitch, int n,
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const uint8_t *transp_color)
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{
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int i;
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for(i = 0; i < n; i++) {
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if (!transp_color[*buf])
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return 0;
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buf += pitch;
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}
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return 1;
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}
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/* return 0 if empty rectangle, 1 if non empty */
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static int find_smallest_bounding_rectangle(AVSubtitle *s)
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{
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uint8_t transp_color[256];
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int y1, y2, x1, x2, y, w, h, i;
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uint8_t *bitmap;
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if (s->num_rects == 0 || s->rects == NULL || s->rects[0].w <= 0 || s->rects[0].h <= 0)
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return 0;
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memset(transp_color, 0, 256);
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for(i = 0; i < s->rects[0].nb_colors; i++) {
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if ((s->rects[0].rgba_palette[i] >> 24) == 0)
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transp_color[i] = 1;
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}
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y1 = 0;
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while (y1 < s->rects[0].h && is_transp(s->rects[0].bitmap + y1 * s->rects[0].linesize,
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1, s->rects[0].w, transp_color))
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y1++;
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if (y1 == s->rects[0].h) {
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av_freep(&s->rects[0].bitmap);
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s->rects[0].w = s->rects[0].h = 0;
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return 0;
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}
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y2 = s->rects[0].h - 1;
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while (y2 > 0 && is_transp(s->rects[0].bitmap + y2 * s->rects[0].linesize, 1,
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s->rects[0].w, transp_color))
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y2--;
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x1 = 0;
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while (x1 < (s->rects[0].w - 1) && is_transp(s->rects[0].bitmap + x1, s->rects[0].linesize,
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s->rects[0].h, transp_color))
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x1++;
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x2 = s->rects[0].w - 1;
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while (x2 > 0 && is_transp(s->rects[0].bitmap + x2, s->rects[0].linesize, s->rects[0].h,
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transp_color))
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x2--;
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w = x2 - x1 + 1;
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h = y2 - y1 + 1;
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bitmap = av_malloc(w * h);
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if (!bitmap)
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return 1;
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for(y = 0; y < h; y++) {
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memcpy(bitmap + w * y, s->rects[0].bitmap + x1 + (y1 + y) * s->rects[0].linesize, w);
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}
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av_freep(&s->rects[0].bitmap);
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s->rects[0].bitmap = bitmap;
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s->rects[0].linesize = w;
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s->rects[0].w = w;
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s->rects[0].h = h;
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s->rects[0].x += x1;
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s->rects[0].y += y1;
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return 1;
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}
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static int dvdsub_close_decoder(AVCodecContext *avctx)
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{
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return 0;
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}
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#ifdef DEBUG
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#undef fprintf
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static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
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uint32_t *rgba_palette)
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{
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int x, y, v;
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FILE *f;
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f = fopen(filename, "w");
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if (!f) {
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perror(filename);
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exit(1);
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}
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fprintf(f, "P6\n"
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"%d %d\n"
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"%d\n",
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w, h, 255);
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for(y = 0; y < h; y++) {
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for(x = 0; x < w; x++) {
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v = rgba_palette[bitmap[y * w + x]];
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putc((v >> 16) & 0xff, f);
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putc((v >> 8) & 0xff, f);
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putc((v >> 0) & 0xff, f);
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}
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}
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fclose(f);
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}
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#endif
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static int dvdsub_decode(AVCodecContext *avctx,
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void *data, int *data_size,
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uint8_t *buf, int buf_size)
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{
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AVSubtitle *sub = (void *)data;
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int is_menu;
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is_menu = decode_dvd_subtitles(sub, buf, buf_size);
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if (is_menu < 0) {
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no_subtitle:
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*data_size = 0;
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return buf_size;
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}
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if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
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goto no_subtitle;
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#if defined(DEBUG)
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av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n",
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sub->start_display_time,
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sub->end_display_time);
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ppm_save("/tmp/a.ppm", sub->rects[0].bitmap,
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sub->rects[0].w, sub->rects[0].h, sub->rects[0].rgba_palette);
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#endif
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*data_size = 1;
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return buf_size;
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}
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AVCodec dvdsub_decoder = {
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"dvdsub",
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CODEC_TYPE_SUBTITLE,
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CODEC_ID_DVD_SUBTITLE,
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0,
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dvdsub_init_decoder,
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NULL,
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dvdsub_close_decoder,
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dvdsub_decode,
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};
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